Optical anisotropy in WS2/ReS2 heterostructure with one-dimensional moiré pattern

Abstract

Two-dimensional (2D) materials with low symmetry have garnered considerable attention due to their anisotropic electrical and optical properties, demonstrating great potential in various fields. Recently, 2D anisotropic/isotropic heterostructures have shown promise in breaking isotropic symmetry and inducing anisotropic responses through precise control of interfacial structures, such as moiré patterns. However, detailed experimental investigations into the correlation between anisotropic behaviors and anisotropic moiré patterns remain scarce. Here, we report optical anisotropy in WS2 by stacking a WS2/ReS2 heterostructure. Through measurements of polarized photoluminescence spectra, we observe that the intralayer excitons (both localized-state exciton LX and neutral exciton XA) of WS2 in the heterostructure exhibit pronounced anisotropy, which remains robust at both room temperature and a low temperature of ∼10 K. Furthermore, the angles between the linear polarization directions and the orientation of the corresponding one-dimensional moiré patterns remain approximately constant values (∼60° for LX and ∼45° for XA), demonstrating a clear correlation between anisotropic exciton emission and the anisotropic moiré patterns. Our work offers valuable insights into achieving artificial optical anisotropy using anisotropic/isotropic heterostructures, paving the way for enhanced performance in anisotropic sensing devices.